Android Button

Android Button

Android Button represent a push-button. The android.widget.Button is subclass of TextView class and CompoundButton is the subclass of Button class.

There are different types of buttons in android such as RadioButton, ToggleButton, CompoundButton etc.

Here,we are goig to create two textfield and one button for sum of two numbers. If user clicks button, sum of two input values is displayed on the Toast.

Now write the code to generate the UI components

File:activity_main

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent">

    <EditText

        android:id="@+id/number1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_marginStart="20dp"

        android:hint="Enter First number"

        android:layout_marginTop="20dp"

        android:layout_marginEnd="20dp"/>

    <EditText

        android:id="@+id/number2"

        android:layout_below="@+id/number1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_marginStart="20dp"

        android:hint="Enter Second number"

        android:layout_marginTop="20dp"

        android:layout_marginEnd="20dp"/>

    <Button

        android:id="@+id/button"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Add"

        android:layout_marginEnd="20dp"

        android:layout_marginStart="20dp"

        android:onClick="addition"

        android:layout_marginTop="15dp"

        android:layout_below="@+id/number2"/>

</RelativeLayout>

Activity class

Now write the code to display the sum of two numbers.

File:MainActivity.java

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    Button b1;

    EditText et1,et2;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        et1= (EditText) findViewById(R.id.number1);

        et2= (EditText) findViewById(R.id.number2);

        b1= (Button) findViewById(R.id.button);

    }

    public void addition(View view) {

        String n1=et1.getText().toString();

        String n2=et2.getText().toString();

        int a=Integer.parseInt(n1);

        int b=Integer.parseInt(n2);

        int sum=a+b;

        Toast.makeText(this, String.valueOf(sum), Toast.LENGTH_SHORT).show();

    }

}

Output: